Uninterruptible Power Supply
UPS is basically composed of three main components, namely:
This section is used to transfer circuit and battery charging. Rectifier-charger circuit block is going to supply the power needed by the inverter under full load and at that time to maintain the charge in the battery. Besides these blocks must have the ability to drain the power output of 125-130%.
Characteristics of the batteries also need to be taken into account in its charger circuit design because if a rechargeable battery with a current that exceeds the capacity limit will be able to shorten the life of the battery. Usually for a battery charging current to the UPS is 80% of current conditions issued by the batteries at full load.
Limitation of a UPS system is good by the standards of NEMA - National
Electical Manufacturer Association - is able to provide 100% power continuously (continuous load) and 2 hours at 125% load without a decrease in performance (damage). The battery can still be categorized as unfit for use if the condition is still capable of providing 100% power for 1 hour if the time of filling for 8 hours (determined by the manufacturing
The quality of the inverter is a determinant of the quality of power generated by a UPS system. Inverter function to change the DC voltage of the rectifier-charger circuit into AC voltage signal in the form of a sine wave formation and after going through the filter circuit. The resulting output voltage must be stable both voltage amplitude and frequency, low distortion, there are no voltage transients.
In addition, the inverter system needs a feedback circuit (feedback) and the regulator circuit to maintain constant voltage to be obtained.
3) Switch Shifters (Transfer switches)
Transfer switch is divided into two types, namely electromechanical and static. Electromechanical switch uses relays to get one of the supply voltage terminal and the other from the UPS system. Static switch system using semiconductor components, such as SCR.
The use of SCR would be better because of the removal operation is performed with the SCR takes only 3 to 4 ms, while the electromechanical switch is about 50 to 100 ms.
The use of UPS is done by connecting the UPS to the AC input and output PLN UPS to the load. Most UPS are used to supply the computer, because if the source of PLN suddenly dies, then the data being processed is not lost but is still in the back-up by UPS, so there's still time to save data.